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Abstract:

An autonomous vibration-driven device, for motion through a lumen or along
a surface, utilizing an array of flexible fibers attached to the body of
the device. The outer surface of the fibers have an anisotropic
coefficient of friction with the surface along which the device is to
move, and the fibers extend from the device body such that at least some
of the fibers are in contact with the walls along a part of their length.
A transducer is used to vibrate the device, such that it moves down the
lumen. The transducer can be either device borne or external. A rotary
device is also described, utilizing an array of fibers disposed on the
rotor's body, the fibers having an anisotropic coefficient of friction
with a central stator or with an outer circular wall. A planar motion
device is also described for crawling over a planar surface.

Claims:

1. A vibration-driven device comprising a body having a plurality of
flexible fibers attached thereto, the surface of at least some of said
fibers having along at least part of their length, anisotropic friction
with at least one juxtaposed surface, said fibers extending from said
body such that at least some of them are in contact with said at least
one juxtaposed surface along part of their length,wherein mutual
vibratory motion between said device and said juxtaposed surface causes
said device to move relative to said at least one juxtaposed surface.

2. A device according to claim 1 and wherein said mutual vibratory motion
arises from a vibration generating system.

3. A device according to either of the previous claims and wherein said
mutual vibratory motion between said device and said juxtaposed surface
comprises vibration of at least one of said body and at least some of
said fibers.

4. A device according to claim 2 and wherein said vibration generating
system comprises an external field which operates on an element disposed
in said device.

5. A device according to claim 4 and wherein said external field is an
alternating magnetic field, and said element disposed in said device
comprises either one of a magnetic material or a magnet.

6. A device according to claim 2 and wherein said vibration generating
system is a transducer disposed on said device.

7. A device according to claim 2 and wherein said vibration generating
system is operative to vibrate said at least one juxtaposed surface.

8. A device according to any of the previous claims and wherein said at
least one juxtaposed surface is the inside wall of a lumen.

9. A device according to claim 8 and wherein said lumen has either one of
a round or a rectilinear form.

10. A device according to claim 8 and wherein said at least one juxtaposed
surface is at least one inside wall of a straight walled conduit.

11. A device according to any of claims 1 to 7 and wherein said at least
one juxtaposed surface is a planar surface.

12. A device according to any of claims 1 to 7 and wherein said body is an
annular body having a central bore, and said at least one juxtaposed
surface is disposed inside said central bore of said annular body.

13. A device according to claim 12 and wherein said at least one
juxtaposed surface disposed inside said central bore of said annular body
is a guide wire or the external wall of a lumen, and said device crawls
therealong.

14. A device according to any of claims 1 to 7 and wherein said at least
one juxtaposed surface is the inside wall of an annular housing, said
device being disposed within said annular housing and said fibers being
attached to said body such that they contact said annular housing
circumferentially, such that said device rotates within said annular
housing.

15. A device according to any of the previous claims 1 to 7 and wherein
said body is an annular body having a central bore, and said fibers are
attached circumferentially to the inside of said central bore, such that
said body rotates round a post disposed within said central bore.

16. A device according to claim 15, further comprising a linear follower
coupled to an outer surface of said annular body, such that said device
generates linear motion in said follower.

17. A device according to claim 8 and wherein said fibers are attached to
said body such that they are all oriented in one direction relative to
the axis of said lumen, such that said device moves along the axis of
said lumen.

18. A device according to claim 8 and wherein said fibers are attached to
said body in groups such that the fibers of one group are oriented in one
direction relative to the axis of said lumen, and those of the other
group in the opposite direction, said device further comprising a
mechanism for deploying and stowing one or the other of said groups of
fibers, such that said device can move along the axis of said lumen in
either direction according to which group of fibers is deployed.

19. A device according to claim 8 and wherein said fibers are attached to
said body in groups, the fibers of a first group being attached to said
body on at least one segment on one side of a diametric plane through the
cross section of said body, said at least one segment being oriented at a
first angle to a line perpendicular to said diametric plane, at least
part of some of said fibers being in contact with said inside wall of
said lumen, and those of a second group being attached to said body on at
least another segment on the opposite side of said diametric plane
through the cross section of said body, said at least another segment
being oriented at a second angle to a line perpendicular to said
diametric plane, said second angle having the opposite sense to said
first angle, such that said device performs both rotary and linear motion
through said lumen when said mutual vibratory motion is actuated.

20. A device according to either of claims 12 and 13, and wherein said
fibers are attached to said central bore of said annular body in groups,
the fibers of a first group being attached to said body on at least one
segment on one side of a diametric plane through the cross section of
said body, said at least one segment being oriented at a first angle to a
line perpendicular to said diametric plane, at least part of some of said
fibers being in contact with said at least one juxtaposed surface, and
those of a second group being attached to said body on at least another
segment on the opposite side of said diametric plane through the cross
section of said body, said at least another segment being oriented at a
second angle to a line perpendicular to said diametric plane, said second
angle having the opposite sense to said first angle, such that said
device performs both rotary and linear motion along said at least one
juxtaposed surface when said mutual vibratory motion is actuated.

21. A device according to either of claims 19 and 20, and wherein the
orientation angles of said segments can be interchanged, such that the
direction of linear motion of said device is reversed.

22. A device according to any of the previous claims and wherein said
anisotropic coefficient of friction with said at least one juxtaposed
surface arises from spikes disposed superficially along at least some of
said fibers.

23. A device according to any of the previous claims and wherein said
anisotropic coefficient of friction with said at least one juxtaposed
surface arises from an anisotropic characteristic of said at least one
juxtaposed surface.

24. A device according to any of the previous claims and wherein said
vibratory motion has a random nature.

25. A device according to claim 1 and wherein said vibration generating
system is a pulsating lumen.

26. A device for autonomous motion through a pulsating lumen, comprising:a
body having a plurality of flexible fibers attached thereto, the surface
of at least some of said fibers having along at least part of their
length, anisotropic friction with the inner wall of said lumen, said
fibers extending from said body such that at least some of them are in
contact with said inner wall of said lumen along part of their length
such that pulsation of said lumen causes said device to move along said
lumen.

27. A device according to claim 26, wherein said pulsating lumen is either
one of a blood vessel of a subject or a portion of the gastro-intestinal
tract of a subject.

28. A vibration-driven device comprising:a body having a plurality of
flexible fibers attached to said body in a spiral form along said body,
the surface of at least some of said fibers having along at least part of
their length, anisotropic friction with at least one juxtaposed surface,
said fibers extending from said body such that at least some of them are
in contact with said at least one juxtaposed surface along part of their
length;wherein mutual vibratory motion between said device and said
juxtaposed surface causes said device to move relative to said at least
one juxtaposed surface.

29. A device according to claim 28 and wherein said at least one
juxtaposed surface is the inner wall of a lumen, such that said device
performs both rotary and linear motion through said lumen when said
mutual vibratory motion is actuated.

30. A device according to claim 29, wherein said fibers are attached to
said body in groups, a first group being attached to said body on at
least one half segment of said spiral on one side of a diametric plane
through the cross section of said spiral, and a second group being
attached to said body on at least another half segment of said spiral on
the opposite diametric side of said spiral cross section, and wherein the
orientation angles which said first and second segments make with a line
perpendicular to said diametric plane can be interchanged, such that the
direction of motion of said device is reversed.

31. A device according to claim 28 and wherein said wherein said body is
an annular body having a central bore, and said at least one juxtaposed
surface is any one of a guide wire or a lumen disposed inside said
central bore of said annular body, such that said device performs both
rotary and linear motion along said guide wire when said mutual vibratory
motion is actuated.

32. A device according to claim 31 and wherein said at least one
juxtaposed surface is the outer wall of said guide wire or lumen, such
that said device performs both rotary and linear motion along said guide
wire or lumen when said mutual vibratory motion is actuated.

33. A device according to claim 32, wherein said fibers are attached to
said body in groups, a first group being attached to said body on at
least one half segment of said spiral on one side of a diametric plane
through the cross section of said spiral, and a second group being
attached to said body on at least another half segment of said spiral on
the opposite diametric side of said spiral cross section, and wherein the
orientation angles which said first and second segments make with a line
perpendicular to said diametric plane can be interchanged, such that the
direction of motion of said device is reversed.

Description:

FIELD OF THE INVENTION

[0001]The present invention relates to a robotic device for crawling over
a surface, whether plane or in a lumen, especially using vibration of the
device to propel it by means of flexible fibers having an external
surface with anisotropic friction with the surface on which the device is
crawling.

BACKGROUND OF THE INVENTION

[0002]Current techniques for providing autonomous motion down a lumen
generally involve a relatively complicated mechanism with multiple moving
parts, which restricts miniaturization because of current technological
limitations. Moreover those techniques often require sequential
controlled actuations, thus complicating their operation.

[0003]Furthermore most methods commonly used cannot operate in confined
spaces such as relatively small pipes, or in environments other than
those predetermined for the device. Due to the complexity, the
multiplicity of moving parts, the possible need of actuators, and control
circuits, sensors and internal power sources, prior art mechanisms suffer
size limitations, have complex assemblies and relatively high cost,
specifically in narrow environments like pipes where miniaturization is
essential. More specifically for medical applications, where there is
demand for biocompatible miniature systems with a minimal number of
moving parts (for medical safety reasons) prior art mechanisms are
generally far from optimal.

[0004]Hence, there is a need for an autonomous miniature moving mechanism
which should be simple, composed of a minimal number of moving parts and
which performs well in different environments.

[0005]Locomotion inspired by the peristaltic motion of Annelids, and
especially of earthworms, has suggested the use of friction between
oscillating microstructures and the wall of a lumen or the surface to be
traversed. Such devices offer promise for a simple robotic autonomous
crawling device.

[0006]The paper entitled "Development of a biomimetic miniature robotic
crawler" published in Autonomous Robots Journal Vol 21(2) pg. 155-163,
describes the development of segmented artificial crawlers endowed with
passive hook-shaped frictional microstructures, using a
Shape-Memory-Alloy spring which causing its torso to alternately shrink
and expand with large amplitude and at low frequencies, thereby, causing
locomotion. The hooks provide the anisotropic friction necessary for the
progress of the device.

[0007]In the paper "In pipe bristled micromachine" published in Advanced
Motion Control, 2002, Pg. 599-603, the micromachine locomotion principle
is based on a directional friction force between the tips of inclined
oscillating bristles and the pipe wall. A small amplitude and high
frequency piezoactuator is used in the device torso.

[0008]In both of these systems the friction-members limits the contact
surface geometry i.e. if applied as an in-pipe moving robot, since no
adjusting mechanism is embodied, the diameter range in which such a robot
can be applied is narrow. Furthermore, the motion is achieved by changing
the distance between two or more anchoring bristles by the use of a size
varying actuator such as a Shape-Memory-Alloy or Piezoelectric actuator.

[0009]U.S. Pat. No. 2,917,762 for "Apparatus for Traveling through Pipes"
to C. P. Xenis, describes an apparatus for in-pipe travel comprised of
inclined stiff fibers arranged in a cylindrical manner, having a diameter
slightly in excess of the inner diameter of the conduit, and which
advances due to vibrations. As described, an inclination angle of about
15 degrees between the fibers and the normal to the longitudinal axis of
the apparatus will generate suitable anisotropic friction with the pipe's
inner surface while in contact. However the fiber's stiffness and the
friction which is induced solely at the tips of the fibers limit the pipe
diameter range to which such an apparatus may be applied. In addition
this apparatus is limited to uses within a pipe.

[0010]U.S. Pat. No. 3,885,356 for "Vibratory Conveyor and Abrader" to J.
W. Armstrong describes a conveyer belt system using a vibrating pile
material having resilient fibers inclined towards the direction of feed,
and vibrated in a direction close to that of the fibers, in order to move
objects placed thereupon. This patent describes specific use only of the
tips of the vibrating fibers for supporting the load and for providing
the motion thereto.

[0011]U.S. Pat. No. 5,575,378 for "Transfer Method and Apparatus Therefor"
to A. J. Billington et al, describes another vibrating fiber conveyer
system, which, instead of fibers, uses a multiplicity of extremely fine
and relatively short flexible fibers packed at an ultra high density pile
to provide a cushion element for moving a load placed on the fibers. The
fibers may also be positioned on an object to move it relative to a base.
Use of this fiber construction avoids damage to fragile objects
transported by the conveyor.

[0012]U.S. Pat. No. 5,770,913 for "Actuators, motors and wheel-less
autonomous robots using vibratory transducer drivers" to J. V. Mizzi
describes a device providing one of an actuator, motor and a wheel-less
autonomous robot using vibratory transducer drivers. The vibratory
transducer driver is connected to a reciprocating element, driven
reciprocally by the vibration driver. A friction surface is provided for
translating reciprocating movement of the reciprocating element into
motion. A driven member is moved by contact with the friction surface.
This patent suggested a "Fibre-Tran" material supplied by the 3M Company
as being a good material for use in the described invention. This
material is based on anisotropic friction using the tips of inclined
fibers.

[0013]Bristle tip-based oscillational crawlers may be limited to specific
spatial situations such as pipes having a predetermined diameter and with
only small variations in diameter, and moreover to specifically
sequential or controlled oscillations. There is a need in the art for an
autonomous robot using the vibrational fiber principle, which overcomes
some of the disadvantages of previous such devices, and which can comply
to a wide and varying range of pipes diameters, and which comprises a
minimal number of moving parts, is low in cost and easy to manufacture.

[0014]The disclosures of each of the publications mentioned in this
section and in other sections of the specification are hereby
incorporated by reference, each in its entirety.

SUMMARY OF THE INVENTION

[0015]The present disclosure describes an autonomous robotic device and
method for crawling along a juxtaposed surface or surfaces using random
vibrations. The device utilizes the effects of the vibrations on the
anisotropic friction properties between the surfaces along the length of
fibers attached to the device, and the surrounding juxtaposed surface or
surfaces. The surrounding surface or surfaces may be the inner wall of a
lumen, two bounding walls for confined planar motion, a plane on which
the device is disposed for two dimensional planar motion or an inner
guide wire on which the device crawls. An example of a rotational engine
is also shown, based on the same principles of superficial anisotropic
friction of fibers attached to the vibrating device.

[0016]The robot is generally comprised of a central torso or body, and
flexible fibers attached as cantilevers at an angle to the central torso.
The fibers should be unloaded if not in contact with any surrounding
surface. The fibers should be sufficiently long that, when the device is
applied to the inner surface walls of the tube it is intended to
negotiate, or to the surface it is intended to crawl along, a portion of
the fiber at the end remote from the torso becomes parallel to the
surface, making contact with the surface along at least a part of its
length. The fibers may have varying flexibility, increasing from base to
tip, to enable flexion in such a way as to assist this effect.

[0017]The surface of the fibers should have an anisotropic coefficient of
friction along at least a portion of their length remote from the torso,
such that they grip the opposing surface more strongly in one direction
of relative motion than in the other direction. This may be achieved by
providing the fibers with spikes extended from their surface, providing
contact with surrounding surfaces through the spikes. The fibers are long
enough to maintain contact with the surrounding surfaces during motion.
The fiber's extended spikes may be slanted at an angle to the fiber,
further referred to as the spike angle. The angle between the spikes and
the co-operating friction surface, further referred to as contact angle,
determines the friction force with the surrounding surface. As a result
of the fiber's flexion, the contact angle is approximately equal to the
spike angle, allowing the maintenance of an optimal and constant friction
force throughout the motion.

[0018]The fibers' spikes provide anchoring points to the surrounding
surface in the direction opposite to the slant of the spikes, thus
stopping backward motion, while enabling slipping movement in their
slanted direction, resulting in an anisotropic friction coefficient. The
locomotion is optimal when the difference between friction forces acting
during movement in opposite directions is maximal. This difference
depends both on the difference between the friction coefficients acting
in opposite directions, and on the distributed normal forces acting on
the contact area with the surrounding surfaces. These two factors depend
upon the extent of the contact area of the fibers with their surrounding
surfaces and upon the contact angle. Thus a proposed structure having a
variable fiber cross section enables optimization of both parameters,
maintaining a constant contact angle, a large normal force, and a long
parallel contact portion of fiber with the surrounding walls. A
particularly simple method of achieving a higher normal force due to a
variable flexibility fiber is by use of fibers having a thicker base end
than that of the tip end. The base end then provides increased stiffness,
and hence increased normal force at the contact end, while the contact
end has the desired increased flexibility to make contact with a longer
section of the opposing surface.

[0019]Since that portion of the fibers making contact with the surrounding
surface is parallel to the surrounding surface, the contact angle remains
constant throughout the motion. The length of the fibers may be such that
they significantly exceed the distance between the device body and the
surrounding surface. If the fibers were stiff, as in prior art vibrating
bristle devices which rely on bristle tip friction, this would be
impractical since the fibers in such devices have only one contact point
at the tip of the fiber, and lengthening the fibers would result in a
smaller angle of contact at the tip, and reduced friction coefficient.
Hence if applied as an in-pipe apparatus, the flexibility of the fibers
in the exemplary devices described in the present application, enables
application of a single one of such devices to a wide range of diameters.
This property makes the invention desirable, for example, for use in
medical applications where arteries, the gastrointestinal tract, and
other internal lumens may vary greatly in diameter along their length.
The considerations above also apply for two bounding walls for confined
planar motion, and for rotational movements which are attractive for use
in Micro Electro Mechanical System (MEMS) applications, but had been
limited till now due to design and manufacturing limitations.

[0020]Locomotion is achieved due to random vibrations in any direction or
plane applied to the torso of the device. A robot constructed according
to these aspects of the present invention progresses due to flexion of
its fibers. Thus, any vibration causing the fibers to flex will result in
progression. One possible actuation embodiment for such devices is to use
an onboard magnet or ferromagnetic slug while inducing a time varying
magnetic field upon it. This example enables unlimited operation time,
since the activation energy for generating the vibration is provided
externally and is not dependent on the use of onboard batteries, while
also maintaining simplicity of operation. It is possible to use magnetic
induced actuation since the vibration does not need to be controlled in
any manner. Any random vibration will enable the device to function
correctly. As an alternative to causing the body to vibrate, it is
possible to generate the vibrations directly in the fibers, such as by
making them of a magnetized or a magnetic material and applying an
external alternating magnetic field, or by any other suitable method.

[0021]A further implementation includes a method for enabling the robot to
move in a two dimensional planar manner. In this case, the fibers are
extended downwards, enabling contact with the plane on which the robot is
to be applied, resulting in a planar motion.

[0022]Other exemplary applications include a method for enabling the robot
to move in a planar manner while being confined by two bounding walls. In
this case fibers are extended sidewards enabling a planar motion while in
contact with the two opposing walls.

[0023]Additional implementations include a rotary device which rotates
within the walls of a generally round external housing, due to its
anisotropic friction fibers and a resulting rotation when vibration is
applied to the device. Such a device is most applicable in MEMS
technology due to its simplicity and due to the lack of a need for either
a shaft axis or a bearing for generating the rotation, though an axis may
be needed in order to transfer the rotation to its intended load.

[0024]All of the exemplary implementations and examples described in this
disclosure illustrating different aspects of this invention, utilize
anisotropic friction generated between the fibers and the surface being
traversed, based on the friction coefficient between the surface of the
fibers and the opposing traversed surface. In order to delineate clearly
between this specific type of anisotropic friction and prior art friction
arising from interaction between the tips of the fibers and the opposing
surface, the frictional property of the surface of the fibers with their
opposing surface is generally called superficial anisotropic friction in
the present application, and this term is thuswise to be understood
throughout the application and as claimed.

[0025]There is thus provided in accordance with different examples of the
present invention, a One example implementation involves, a
vibration-driven device comprising a body having a plurality of flexible
fibers attached thereto, the surface of at least some of the fibers
having along at least part of their length, anisotropic friction with at
least one juxtaposed surface, the fibers extending from the body such
that at least some of them are in contact with the at least one
juxtaposed surface along part of their length,

wherein mutual vibratory motion between the device and the juxtaposed
surface causes the device to move relative to the at least one juxtaposed
surface.

[0026]In such a device, the mutual vibratory motion may arise from a
vibration generating system. Such a vibration generating system may
comprise an external field which operates on an element disposed in the
device. In such a case, the external field may be an alternating magnetic
field, and the element disposed in the device may be either a magnetic
material or a magnet. Alternatively, the vibration generating system may
simply be a transducer disposed on the device. In any of these examples,
the vibration generating system may be operative to vibrate the at least
one juxtaposed surface. Furthermore, the mutual vibratory motion between
the device and the juxtaposed surface may comprise vibration either of
the body or of at least some of the fibers.

[0027]In any of the above described devices, the at least one juxtaposed
surface may be the inside wall of a lumen. This lumen may have either a
round or a rectilinear form. Alternatively, the at least one juxtaposed
surface may be at least one inside wall of a straight walled conduit.

[0028]Additionally, in alternative implementations of any of the
above-described devices, the at least one juxtaposed surface may be a
planar surface.

[0029]Alternatively, the body may be an annular body having a central
bore, and the at least one juxtaposed surface may be disposed inside the
central bore of the annular body. In such a case, the at least one
juxtaposed surface disposed inside the central bore of the annular body
may be a guide wire or the external wall of a lumen, and the device may
crawl therealong.

[0030]Another example implementation can involve a device in which the at
least one juxtaposed surface is the inside wall of an annular housing,
the device being disposed within the annular housing and the fibers being
attached to the body such that they contact the annular housing
circumferentially, such that the device rotates within the annular
housing.

[0031]Alternatively, the body may be an annular body having a central
bore, and the fibers may be attached circumferentially to the inside of
the central bore, such that the body rotates round a post disposed within
the central bore. In such an example, the device may further comprise a
linear follower coupled to an outer surface of the annular body, such
that the device generates linear motion in the follower.

[0032]In those examples where the device crawls within a lumen, the fibers
may be attached to the body such that they are all oriented in one
direction relative to the axis of the lumen, such that the device moves
along the axis of the lumen. Alternatively, the fibers may be attached to
the body in groups such that the fibers of one group are oriented in one
direction relative to the axis of the lumen, and those of the other group
in the opposite direction, the device further comprising a mechanism for
deploying and stowing one or the other of the groups of fibers, such that
the device can move along the axis of the lumen in either direction
according to which group of fibers is deployed.

[0033]In such cases of motion through a lumen, the fibers may
alternatively be attached to the body in groups, the fibers of a first
group being attached to the body on at least one segment on one side of a
diametric plane through the cross section of the body, the at least one
segment being oriented at a first angle to a line perpendicular to the
diametric plane, at least part of some of the fibers being in contact
with the inside wall of the lumen, and those of a second group being
attached to the body on at least another segment on the opposite side of
the diametric plane through the cross section of the body, the at least
another segment being oriented at a second angle to a line perpendicular
to the diametric plane, the second angle having the opposite sense to the
first angle, such that the device performs both rotary and linear motion
through the lumen when the mutual vibratory motion is actuated.

[0034]Likewise, in the case of a device crawling along the at least one
juxtaposed surface, the fibers may be attached to the central bore of the
annular body in groups, the fibers of a first group being attached to the
body on at least one segment on one side of a diametric plane through the
cross section of the body, the at least one segment being oriented at a
first angle to a line perpendicular to the diametric plane, at least part
of some of the fibers being in contact with the at least one juxtaposed
surface, and those of a second group being attached to the body on at
least another segment on the opposite side of the diametric plane through
the cross section of the body, the at least another segment being
oriented at a second angle to a line perpendicular to the diametric
plane, the second angle having the opposite sense to the first angle,
such that the device performs both rotary and linear motion along the at
least one juxtaposed surface when the mutual vibratory motion is
actuated.

[0035]In either of these previous two exemplary devices, the orientation
angles of the segments can be interchanged, such that the direction of
linear motion of the device is reversed.

[0036]In any of the above described exemplary devices, the anisotropic
coefficient of friction with the at least one juxtaposed surface may
arise either from spikes disposed superficially along at least some of
the fibers or from an anisotropic characteristic of the at least one
juxtaposed surface.

[0037]Furthermore, the vibratory motion may have a random nature.
Additionally, the vibration generating system may be a pulsating lumen.

[0038]Other implementations described in this disclosure may relate to a
device for autonomous motion through a pulsating lumen, comprising a body
having a plurality of flexible fibers attached thereto, the surface of at
least some of the fibers having along at least part of their length,
anisotropic friction with the inner wall of the lumen, the fibers
extending from the body such that at least some of them are in contact
with the inner wall of the lumen along part of their length such that
pulsation of the lumen causes the device to move along the lumen. In such
a device, the pulsating lumen may be either one of a blood vessel of a
subject or a portion of the gastro-intestinal tract of a subject.

[0039]Even further exemplary implementations described in this disclosure
may be for a vibration-driven device comprising a body having a plurality
of flexible fibers attached to the body in a spiral form along the body,
the surface of at least some of the fibers having along at least part of
their length, anisotropic friction with at least one juxtaposed surface,
the fibers extending from the body such that at least some of them are in
contact with the at least one juxtaposed surface along part of their
length, and wherein mutual vibratory motion between the device and the
juxtaposed surface may cause the device to move relative to the at least
one juxtaposed surface.

[0040]In such a device, the at least one juxtaposed surface may be the
inner wall of a lumen, such that the device performs both rotary and
linear motion through the lumen when the mutual vibratory motion is
actuated. In this case, the fibers may be attached to the body in groups,
a first group being attached to the body on at least one half segment of
the spiral on one side of a diametric plane through the cross section of
the spiral, and a second group being attached to the body on at least
another half segment of the spiral on the opposite diametric side of the
spiral cross section, and wherein the orientation angles which the first
and second segments make with a line perpendicular to the diametric plane
can be interchanged, such that the direction of motion of the device is
reversed.

[0041]According to further examples of vibration-driven devices comprising
a body having a plurality of flexible fibers attached to the body in a
spiral form along the body, as mentioned above, the body may be an
annular body having a central bore, and the at least one juxtaposed
surface may be either a guide wire or a lumen disposed inside the central
bore of the annular body, such that the device may perform both rotary
and linear motion along the guide wire when the mutual vibratory motion
is actuated.

[0042]In such a device, the at least one juxtaposed surface may be the
outer wall of the guide wire or lumen, such that the device performs both
rotary and linear motion along the guide wire or lumen when the mutual
vibratory motion is actuated. In this case, the fibers may be attached to
the body in groups, a first group being attached to the body on at least
one half segment of the spiral on one side of a diametric plane through
the cross section of the spiral, and a second group being attached to the
body on at least another half segment of the spiral on the opposite
diametric side of the spiral cross section, and the orientation angles
which the first and second segments make with a line perpendicular to the
diametric plane may be interchanged, such that the direction of motion of
the device may be reversed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043]The presently claimed invention will be understood and appreciated
more fully from the following detailed description, taken in conjunction
with the drawings in which:

[0044]FIG. 1 illustrates schematically a linear motion vibrating robotic
crawler constructed and operative according to a first preferred
embodiment of the present invention;

[0045]FIG. 2A is an enlarged view of one of the fibers shown in FIG. 1, to
illustrate one exemplary manner by which the fibers are given their
anisotropic friction coefficient with a surface with which they have
contact; FIG. 2B shows such a fiber, as machined from a thin sheet of
metal or etched from a suitable substrate material;

[0046]FIG. 3A is a schematic drawing of the crawling device of FIG. 1
inserted into a tube, to illustrate how the device functions; FIG. 3B
illustrates schematically a vibratory crawling device for operation in a
planar conduit having generally flat side walls; FIG. 3C illustrates
schematically a vibratory crawling device for operation on a planar
surface;

[0047]FIG. 4 illustrates schematically a crawling device, based on the
example shown in FIG. 3A, but capable of motion in either direction;

[0049]FIG. 6A illustrates schematically a vibratory anisotropic friction
motion device, similar to that shown in FIG. 5 except that the flexible
fibers are attached internally to an outer rotor which rotates; FIG. 6B
illustrates the use of the device of FIG. 6A to produce linear motion;
FIG. 6C illustrates the achievement of higher rotational or linear speed,
or torque multiplication using the device of FIG. 6A;

[0050]FIG. 7 schematically shows further examples showing a vibration
operated crawling device having an annular cylindrical form which can
crawl along a central axial element, such as a guide wire;

[0051]FIGS. 8A to 8D illustrate schematically a further example of a
crawling device, which combines linear motion with circular motion; and

[0052]FIG. 9 illustrates schematically a further exemplary device, similar
to that of FIGS. 8A to 8D, except that the spiral arrangement of fibers
is located on an internal annular wall of the device, such that it can
crawl along a guide wire or the outside surface of a lumen, while also
rotating,

DETAILED DESCRIPTION

[0053]Reference is now made to FIG. 1 which illustrates schematically an
example of a linear motion vibrating robotic crawler 10 according to one
aspect of the present invention. To the body 11 of the device may be
attached a number of flexible fibers 12 having superficial anisotropic
friction with the opposing surface relative to which the robotic crawler
is intended to move. The fibers are attached to the body such that they
are generally oriented at angles having the same sense to the axis of the
body 11. In FIG. 1, the fibers are all shown oriented to the right of the
drawing, meaning that they make an acute angle with the axis in the
direction towards the right of the drawing. Although the fibers are all
shown inclined at the same attachment angle in FIG. 1, this is not an
essential condition for the operation of the device, and it will function
so long as a majority of the fibers are generally inclined in one
direction relative to a plane perpendicular to the axis of the body. The
body of the crawler preferably contains a transducer 14, which, when
activated, causes the body to vibrate. There is no requirement that the
vibration be in any particular direction for the device to operate, and
it can be completely random. The device will also operate, though, if the
vibration is of an ordered nature, such as linear, oscillating,
reciprocating or circular. The transducer can be self powered, such as by
using an internal battery, and the vibration may then be generated by
means of a piezoelectric element. Alternatively, the vibration can be
activated externally, such as by means of an external AC magnetic field
16 operating on a magnetic slug in the body, or an external AC electric
field acting on a dielectric slug in the body.

[0054]Reference is now made to FIG. 2A, which is an enlarged view of a
circled portion 15 of one of the fibers 12 shown in FIG. 1, to illustrate
one example by means of which the fibers are given their anisotropic
friction coefficient with the surface. The surface of the fiber may be
provided with a number of spikes 20 having a sawtooth profile, with the
sawteeth inclined in the direction of orientation of the fiber, which, in
FIG. 2A is to the top-right of the drawing. When such a spiked fiber
brushes against a surface which has a level of roughness such that the
points of the spikes can catch in the roughness features of the surface,
an anisotropic frictional effect is generated. In the embodiment of FIG.
2A, the fiber can readily move over the surface in a direction towards
the bottom-left of the drawing, but not towards the top-right.
Alternatively, the fibers can be generally smooth, with only some
residual surface roughness, and the anisotropic friction generated by
ensuring that the surface on which the fiber is to brush, has features
such as the spikes of FIG. 2A, which will enable easy sliding motion in
one direction, but not in the reverse direction. This "reversed role"
feature is understood to be applicable not only to the example shown in
FIG. 2A, but also to all of the exemplary vibratory devices in this
application.

[0055]Although the fibers are shown in FIG. 2A as being of round
configuration, this is not meant to limit the invention, but they can
have any readily available profile preferred. For example, because of the
small size of the fibers, according to one example, as shown
schematically in FIG. 2B, they can be laser machined from a thin sheet
22, such as by using a finely focused, industrial cutting-mode laser, or
by etching from a suitable substrate material. According to this example,
the spikes are generated by cutting the fiber profile with integral
spikes 24. In such an example, the height of the "fiber" can be as small
as a few hundred microns. The fibers may also be fabricated using MEMS or
Nano technologies which can result in even smaller dimensions.

[0056]Reference is now made to FIG. 3A, which is a schematic drawing of
the crawling device 10 of FIG. 1 inserted into a tube, 30, to illustrate
how the device functions. The radially dispersed locations of the fibers
ensure that the device is supported generally near the central axis of
tube 30. The vibration transducer 14 causes the device to vibrate when
activated, the body undergoing a zig-zag vibrational motion, and this
causes the device to move in a direction opposite that of the of the
fiber inclination because of the superficial anisotropic frictional
effect between the surfaces of the fibers and the tube inner wall. In the
example shown in FIGS. 2A, 2B and 3A, the crawler moves to the left. It
is clear that the nature of the vibration can be random; all that is
required is that at some instants of time, the vibrations cause some of
the fibers to move in their low friction direction, until they are
latched by means of the spikes in a new location, followed by a similar
motion on the opposite side of the device. The spikes remain latched
until moved even further in their low friction direction by another
vibrational excursion of the same nature. Although the tube in FIG. 3A is
shown as a circular tube, it is to be understood that the invention is
not limited to this shape, but that the device can negotiate any shaped
tube which interacts correctly with the vibrating fibers of the device.
In particular, planar geometries, such as are to be found in MEMS
applications, can be traversed using fibers attached to the body at two
opposite sides to contact the planar walls of a conduit, as will be
illustrated below in the embodiment of FIG. 3B.

[0057]As an outcome of this mechanism of motion, it is clear that the
vibrations do not have to originate in the body of the device, but can be
generated by vibration of the fibers themselves, such as could be
achieved using ferromagnetic fibers with an alternating magnetic field.

[0058]The flexibility of the fibers 12 enables the crawler to fit into
lumens of widely varying diameters, with the lumen walls interacting with
the parallel portion of the fibers 12 which may be in contact with the
wall over a significant part of their length. This enables application of
a single-sized device to a wider diameter range of tubes than is possible
with prior art devices, which use the tips of bristles against the tube
walls to provide the anisotropic friction. This makes the device
particularly advantageous for use in medical applications where blood
vessels, the gastrointestinal tract, and other internal lumens may vary
greatly in diameter along the section to be negotiated by the device.
Additionally, the efficiency of motion may be improved due to the large
section of each fiber which interacts with the surrounding walls.

[0059]According to a further example, the crawler device need not have its
own vibration generating mechanism at all, but the vibrations could be
generated in the walls of the tube. The embodiment where the tube
vibrates longitudinally clearly generates slipping of the fibers along
the walls of the tube, and longitudinal motion. However, the wall
vibrations may even be directed in a radial direction, perpendicular to
the axis of the tube, such that the walls of the tube pulsate in and out,
thus causing fibers to lift off and remake contact with the walls in a
random manner, and thus to propel the crawling device. Such an embodiment
is particularly useful for application in a device for crawling within a
blood vessel, where it is the pulsation of the blood vessel which causes
the device to move down the vessel.

[0060]Reference is now made to FIG. 3B, which illustrates schematically
another example of a vibratory crawling device 32 based on the
above-described functions, for operation in a planar conduit having
generally flat side walls 33. The superficially anisotropic friction
fibers 34 contact the rectilinear side walls 33, and propel the body 35
when the device vibrates. Such a planar conduit architecture is common in
micromechanical structures, such that this embodiment is particularly
useful as a MEMS implementation.

[0061]Reference is now made to FIG. 3C, which illustrates schematically a
vibratory crawling device 36 based on the above-described functions, for
operation on a planar surface 38. The superficially anisotropic friction
fibers 37 are in contact with the planar surface, and as a result of the
generally random vibrations of the device, they lift off and remake
contact with the planar surface, in some instances landing with their
spikes further along the low-friction direction of the planar surface,
and thus generate motion in the direction of the arrow.

[0062]Reference is now made to FIG. 4 which illustrates schematically a
crawling device, based on the examples shown in FIG. 3, but capable of
motion in either direction. The device has two sets of fibers, 40, 42
each oriented in an opposite direction, and a mechanism or mechanisms 44
for either deploying or stowing each set separately. Direction of motion
is dependent on which set of fibers is deployed. In the example shown in
FIG. 4, the deployed set of fibers 40 generates motion from right to
left. Motion in either direction can also be achieved by switching the
direction of the fibers, or having different resonating frequencies of
the fibers and using different frequencies of vibrations for altering
direction of movement of the device.

[0063]Reference is now made to FIG. 5, which illustrates schematically a
further example of an implementation of the present invention, showing a
vibratory superficial anisotropic friction motion device capable of
spindle-less rotation. The device has a central body part 50, which may
have an on-board vibrational transducer 51, and a number of fibers 52
radiating from the central body, and inclined at an angle other than
radially outwards from the body. The fibers should be generally inclined
in the same angular direction relative to the radial direction from the
body. The device sits within an outer circular wall 54, and the surface
of the fibers have an anisotropic coefficient of friction with the walls,
as previously explained hereinabove. As the device vibrates, it generates
one-way motion of the fibers around the casing wall, thus producing
circular motion. For the example shown in FIG. 5, the direction is
clockwise. The device needs no axle on which to run, and is simply
contained in position within the casing walls. Such spindle-less
operation is significantly advantageous for use in MEMS applications,
where it is difficult to fabricate a free running rotating device on, for
example, a silicon substrate, because of the level of internal rotational
friction with a silicon-on-silicon spindle. The exemplary device of FIG.
5 also has significant advantages over prior art circular motors, such as
that shown in U.S. Pat. No. 5,770,913, which requires both a spindle for
operation, and a source of externally applied linear oscillations
producing reciprocating motion.

[0064]Reference is now made to FIG. 6A, which illustrates schematically a
further example of an implementation of the present invention, showing a
superficial anisotropic friction motion device, similar to that shown in
FIG. 5 except that the flexible fibers 60 are attached internally to an
outer rotor 62, and the drive surface is in the form of a smaller
diameter circular static element 64 disposed within the outer rotor near
or at the center of the device. In operation, either the outer rotor or
the inner friction surface, or both are vibrated in order to generate the
circular motion. Unlike the embodiment of FIG. 5, this embodiment does
use a "spindle" for operation, but not in the usual sense of a pivot on
which the rotor revolves. In this case, the "spindle" is the central
stator element, and only the fibers ride on the stator. Since there is
minimal friction in the direction of rotation, it is feasible that this
embodiment is readily implementable in silicon for MEMS use. For the
embodiment shown in FIG. 6A, the direction is clockwise.

[0065]Reference is now made to FIG. 6B, which illustrates schematically a
further exemplary implementation of the present invention, showing a
preferred use of the embodiment of FIG. 6A to generate linear motion. A
linear follower 65, capable of limitless linear movement, is coupled to
the rotor 62 of FIG. 6B by means of rack and pinion gears 66, 67. A
possible application for such an implementation is in the MEMS field
where large linear movements are desired but are difficult to generate.
For the example shown in FIG. 6B, the direction of linear motion of the
follower 65 is from right to left.

[0066]Reference is now made to FIG. 6C, which illustrates schematically a
further example of a device for achieving higher rotational speed, or
higher linear velocity of the follower, or torque multiplication by using
the circular motion illustrated in FIG. 6A combined with gear 69 on an
idler rotor of different diameter. Rotor 69 may be attached also to a
linear follower 68 having a complying gear set to yield a linear motion
with a set velocity. For the embodiment shown in FIG. 6C, the direction
of rotation of the rotor 69 is counterclockwise and the direction of
linear motion of the linear follower is from left to right.

[0067]Reference is now made to FIG. 7, which illustrates schematically a
further example for an implementation of the present invention, showing a
vibration-operated, superficial anisotropic vibratory crawling device 70
having an annular cylindrical form which can crawl along a central
axially arranged element, such as a guide wire 72. The fibers 74 are
arranged on the inside volume of the annular cylinder, so as to contact
the guide wire along its length, and vibration of the device causes it to
crawl along the guide wire. This embodiment is useful for medical
applications where a preliminary guide wire is commonly used to define
the path of the lumen to be negotiated. For the example device shown in
FIG. 7, the direction of motion is from right to left.

[0068]Reference is now made to FIG. 8A which illustrates schematically a
further example of a crawling device, which combines linear motion with
circular motion, such that the device can be used, for instance, for
cleaning the inner walls of the lumen by the rotary motion, and at the
same time, proceeding along a lumen. The device is thus suitable for
self-propelled internal cleaning of a lumen along the whole length that
the device can traverse.

[0069]In this example, the fibers 81 are arranged in a generally spiral
form along the length of the body 84. The fibers are thus generally
aligned at an angle to the axis of the body. Vibration of the body and
hence of the fibers thus generates two components of motion between the
fibers and the wall of the lumen--one component arising from
circumferential contact of the fiber with the wall, and the consequent
component of frictional force between the fiber and the wall in a
tangential direction, this causing the body to rotate, and a second
component arising from the angle which the fibers make with the axis of
the body, and the consequent component of frictional force between the
fiber and the wall in an axial direction, causing the body to move along
the length of the lumen. Such a spiral arrangement of fibers would thus
generate rotational and linear motion down the lumen.

[0070]However, it would be useful to enable the direction of linear motion
to be reversed, such that in medical applications for instance, the
device can be sent in one direction down a lumen, and then retrieved by
motion in the reverse direction. This could be achieved by reversing the
pitch direction of the spiral, which would result in completely reversed
motions. Such an effect can be achieved by viewing the spiral as being
slit in half down along its length, and regarding each segment of the
split spiral as a separate fiber bearing element, such that the segments
on each half of the device can be regarded as semi-discs, whose angle
with the body axis can be reversed by means of a mechanical device.
Referring again to FIG. 8A, the segments in the top half of the drawing
of the device are labeled 82, while those of the bottom half are labeled
83. The segments can be in the form of planes, or as sections of a spiral
screw structure. The segments on opposite sides of the spiral split line
have angles with opposite inclinations to the axis of the body. By this
means, the longitudinal component of the frictional force from the fibers
on both groups of segments operate in the same direction. Thus, referring
to the exemplary construction shown in FIG. 8A, one segment 82 is
inclined at a predetermined angle to the axis of the device such that the
inclination of the fibers causes the device to move under vibration from
left to right of the drawing. The other segments 83 are inclined at an
opposite angle to the axis of the device such that the inclination of the
fibers also causes that second segment 83 to move under vibration from
left to right of the drawing, The fibers can either be mounted at
separate segmental positions on the body, which can also conveniently be
alternate positions, as shown in the plan view of the device in FIG. 8B,
or fibers can be mounted on two sections of a plane at the same axial
position on the device, as shown in FIG. 8C. It is to be understood that
the segments do not have to be physical structures, but are used merely
to illustrate the positions at which the fibers are attached to the body
of the device.

[0071]The device shown in the various exemplary implementations in FIGS.
8A to 8C is thus able to traverse a lumen and at the same time to undergo
rotational motion, which could be used for a cleaning operation. In order
to provide the device with the ability to move in either direction, the
angles which the segments make with the axis of the device may be
reversed, and the axial motion will reverse its direction. This is shown
in the plan view of FIG. 8D, which shows the segments of the example
shown in FIG. 8B with their orientations reversed, such that the device
will now move from left to right using the parameters and terminology of
FIG. 8A. In order to implement such a reversal of angle, it may be
convenient to mount the fibers on physical structures, such as sections
of disc, so that their planar angle can be readily changed by motion of
the angle of these structures. This motion can readily be performed, such
as by means of an electro-mechanical miniature mechanism, or a MEMS,
which can easily be actuated by wireless when desired, ob by any other
mechanism known in the art. The ratio between the rotational speed and
the axial speed can be adjusted by changing the angle between the
segments and the axis of the body, where smaller angle means lower
rotation to axial speed ratio and larger angle means higher rotation to
axial speed ratio.

[0072]Reference is now made to FIG. 9, which illustrates schematically a
further exemplary device, similar to that of FIGS. 8A to 8D, except that
the spiral arrangement of fibers 91 is located on an internal annular
wall of the device, such that it can crawl along a guide wire or the
outside surface of a lumen 94, while also rotating, such as to clean the
surface. In FIG. 9, two sets of segments of the spirally arranged fibers
are shown, segments 92 oriented in one direction to the perpendicular to
the spiral diametric plane shown, and segments 93 oriented in the
opposite direction. As explained regarding the embodiment of FIGS. 8A to
8D, reversal of the orientation angles by means of a mechanical, or other
method, results in reversal of the direction of linear motion of the
device. FIG. 9 shows only the spatial arrangement of the fibers around
the internal bore of the annular body, the other parts of the device
being as shown in the previous examples.

[0073]The ability of the various examples of the vibrating crawling robot
described in this application to move autonomously, and especially those
examples suitable for crawling through lumens, provides these devices
with the ability to perform a number of tasks, especially in the medical
field, which would otherwise be difficult, invasive or impossible. In
most of the applications described, the motion of the robot crawler must
be controlled to reach the desired target position, or alternatively, if
its motion cannot be controlled, such as in fully autonomous applications
where the pulsating lumen is the driving force of the device, then the
progress of the robot must be monitored, and its operational function
activated at a desired target point. One particularly simple method of
controlling the navigation of the robot for such applications is by using
an externally applied alternating magnetic field. Activation of the
desired functions of the robot, can be performed wirelessly, such as by
means of electro-mechanical on-board actuation. Descriptions of a number
of such applications follow, though it is to be understood that these are
only some examples of the potential use of the device, and the invention
is not meant to be limited by or to these applications.

[0074](i) Targeted Drug delivery, using a payload of an enzyme or drug for
delivery to a specific area. Drug targeting, as opposed to conventional
drug delivery, generates high concentrations of the pharmacologically
active agent at the relevant patho-physiologically site, resulting in a
significant reduction in drug toxicity, reduction of the drug dose, and
increased treatment efficacy. Another approach for drug targeting is the
delivery of a biologically active agent (enzyme) to the relevant site
instead of the actual drug, which reduces the payload volume needed to be
carried to the relevant site, and enables interaction with the drug
released in the blood for a longer period of time. Use of the vibrating
crawling robot described herein enables physical delivery of drugs or
enzymes to a desired target in a safe and simple manner. The motion of
the robot crawler must be controlled to reach the desired target spot,
and the payload must be controlled to be released at a desired target
point.

[0075](ii) Vessel occlusion, especially of blood vessels supplying tumors.
The doses of chemotherapy necessary to achieve complete tumor eradication
may be associated with unacceptably high toxicities. The selective
thrombosis of tumor blood vessels has been postulated as an alternative
avenue for combating cancer, by depriving tumors of nutrients and oxygen
and causing an avalanche of tumor cell deaths. Vascular targeting
strategies, aimed at the selective occlusion/disruption of tumor blood
vessels, has been shown to have a significant anticancer therapeutic
potential and encourage the use of antibody-photosensitizer conjugates
for the therapy of superficial tumors and possibly other
angiogenesis-related pathologies. Use of a vibrating crawling robot of
the type described hereinabove enables such an occlusion or flow
disruption to be achieved in a safe and simple manner.

[0076](iii) Intra-coronary arteries pressure and flow sensing. A vibrating
crawling robot of the type described hereinabove, may be used to reach a
specific target while carrying a sensor payload for locally monitoring a
physiological characteristic, such as pressure, flow, glucose levels, or
another readily measured parameter. The robot enables targeted and
constant monitoring capabilities. It can also be used in other
environments besides blood vessels, such as the ureter, parts of the GI
tract, and other bodily lumens.

[0077](iv) Infra pulmonary measurements. A vibrating crawling robot of the
type described hereinabove can be released from the end of a pulmonary
catheter, to reach areas of the lungs which the catheter cannot reach,
and to retrieve information from there. The robot is inserted using a
catheter that passes through relatively large diameter bodily lumens,
such as the bronchial tubes in the lungs, and is then released to
negotiate smaller passages which the catheter cannot negotiate, such as
the bronchioles.

[0078](v) Intra-cranial motion. This is similar to the previous
application in that the robot crawls within the ventricles, for instance
to place an electrode or to sense an area.

[0079](vi) Shunt maintenance. A vibrating robot crawler of the type
described hereinabove may be used for cleaning cerebro-spinal fluid (CSF)
shunts used to treat hydrocephalus or normal pressure hydrocephalus
patients. The micro robot moves through shunts for cleaning and
preventing shunts occlusions, without interfering with the cerebrospinal
fluid (CSF) drainage. This use is applicable for any internal shunts
intended for long term use, such as Hydrocephalus shunts, urethral
catheters, vesicostomy, peritoneal dialysis, and others.

[0080]Referring to the example of the CSF shunt, internal hydrocephalus
can be successfully treated by placing a drainage tube (shunt) between
the brain ventricles and the abdominal cavity to eliminate the high
internal pressures. Alternatively, the drainage tube may be introduced
into the internal jugular vein through a neck incision. A common
complication, generally occurring in the first few months after shunt
placement, is shunt blockage due to choroid plexus or blood clots created
at the insertion point. A micro robot of the vibrating crawling type
described hereinabove, is capable of crawling in tubes, and is ideal for
opening occlusions in such shunts, often preventing the need for shunt
revision procedures. Alternatively, the device can be used to crawl along
their outer surface, possibly using the internal spiral device of FIG. 9,
and to clear any occlusions in drainage holes in the shunt or associated
tubing.

[0081](vii) Prostate gland treatment. A vibrating robot crawler of the
type described hereinabove may be used for reaching the region of the
prostate, carrying with it an antenna or other heating device, to apply
local heating to remove obstruction of flow.

[0082](viii) Gastro-intestinal monitoring. A vibrating robot crawler of
the type described hereinabove may be used for wirelessly monitoring and
recording GI movement by traversing through the GI tract, while being
able to pause at desired regions, and to go back and forth while taking
images from within and collecting biopsies, thus replacing conventional
colonoscopy procedures.

[0083](ix) Gastric or GI excitation for obesity or depression treatment.
Neural messages carried by the vagus nerve play a significant role in the
regulation of ingestion, digestion and satiety. The vagal nerves begin in
the brain and extend to multiple organs and regions of the digestive
system. Each vagus nerve provides direct two-way communication between
the brain and the digestive system without the additional spinal cord
processing of impulses that is typical for most other human nerves. The
vagal nerve trunks are approximately 3-4 mm in diameter and course along
the anterior (front) and posterior (back) of the esophagus before they
branch out from the esophagus to the stomach, pancreas, duodenum and gall
bladder.

[0084]The use of the medical procedure called vagal blocking for obesity
control (VBLOC) has successfully demonstrated the ability to decrease the
volume of pancreatic exocrine secretions by nearly 90% and to inhibit
gastric contractions. This has produced weight loss as a result of
reduced calorie ingestion and absorption, early satiation and prolonged
satiety.

[0085]However VBLOC is an invasive procedure delivered through
laparoscopically implanted leads to intermittently block vagal nerve
trunks. A vibrating robot crawler of the type described hereinabove may
be used for reaching the correct location on the vagus nerves to perform
vagal blocking. The autonomous robot may be swallowed as a particularly
non-invasive method of deployment, and wirelessly targeted, possibly
using an on-board wirelessly actuated transducer, to the vagus nerve in a
predetermined location. The robot may encapsulate a neurostimulator
which, once the correct location has been reached, will generate
electrical stimuli in the form of electrical impulses according to a
pre-programmed regimen for the vagus. According to one exemplary
implementation of a system for this application, the robot may be in the
form of a swallowable pill, including:

(a) Wireless stimulating electrodes.(b) A degradable (DPS) set of fibers
enabling accurate autonomous targeting of the robot.(c) A degradable
anchoring means, to strongly grip the stomach wall, for a limited period
of typically up to a month.(d) An adaptive external control unit for
controlling the robot.

[0086](x) ENT applications. A vibrating robot crawler of the type
described hereinabove may be used for the insertion of electrodes into
the cochlea of the ear, which are otherwise difficult to access
non-invasively by conventional means.

[0087](xi) Stent placement. A vibrating robot crawler of the type
described hereinabove may be used to restore an open pathway or lumen in
a body conduit such as a blood vessel or other body lumen which has
become stenosed or occluded. The robot, after reaching the stenosed area,
expands in the form of a stent for restoring the stenosed or occluded
blood vessel.

[0088](xii) Industrial applications. A vibrating robot crawler of the type
described hereinabove may be used in numerous industrial applications
where it is necessary to navigate pipes or conduits, especially those
having different dimensions along their length. A water, gas or oil leak
scanning robot is thus able to navigate and detect leaks within a
pipeline having changing diameters.

[0089]It is appreciated by persons skilled in the art that the present
invention is not limited by what has been particularly shown and
described hereinabove. Rather the scope of the present invention includes
both combinations and subcombinations of various features described
hereinabove as well as variations and modifications thereto which would
occur to a person of skill in the art upon reading the above description
and which are not in the prior art.

Patent applications by Moshe Shoham, Hoshaya IL

Patent applications by Nir Shvalb, Nesher IL

Patent applications in class With tool carried on endoscope or auxillary channel therefore

Patent applications in all subclasses With tool carried on endoscope or auxillary channel therefore